A very common problem in new constructions is the installation of radiators in series. This means that the return of one radiator is the supply of the next and the next after that one. This means that the first radiator receives all the hot water, the second one a little bit less, and the 3rd/4th/5th receives very little. We see this along single apartments or through several apartments. The problem is that the first room will be over heated while the next rooms won't have enough heat. We also see TRVs installed on the first radiator. In this case the occupant of the first room will turn the TRV down since they are getting all the heat, which will turn the heat off for the following rooms.
The solution is to convert these radiators from series to parallel. Below is an explanation from Danfoss on how this is done as well as some pictures of our conversions from series to parallel.